U.S. patent number 5,932,865 [Application Number 08/762,978] was granted by the patent office on 1999-08-03 for anti-counterfeit validation method for electronic cash cards employing an optical memory stripe.
This patent grant is currently assigned to Drexler Technology Corporation. Invention is credited to Jerome Drexler.
United States Patent |
5,932,865 |
Drexler |
August 3, 1999 |
Anti-counterfeit validation method for electronic cash cards
employing an optical memory stripe
Abstract
A method and system for inhibiting the counterfeiting of
electronic cash smart cards that use microchips for monetary stored
value. Such cards have recently been counterfeited by the use of
electronic techniques to break the security codes. Such
counterfeiting can be inhibited by bonding an optical memory stripe
to the smart card with pre-recorded or post-recorded validation
data on the cards. This optical validation data would be read with
a photodetector array and could be transmitted to the recipient
during funds transfer and/or used locally to control dispensing of
cash. Thus successful counterfeiting of the modified electronic
cash card would require meeting exacting electronic and optical
requirements.
Inventors: |
Drexler; Jerome (Los Altos
Hills, CA) |
Assignee: |
Drexler Technology Corporation
(Mountain View, CA)
|
Family
ID: |
25066566 |
Appl.
No.: |
08/762,978 |
Filed: |
December 9, 1996 |
Current U.S.
Class: |
235/487; 235/380;
235/382; 235/454 |
Current CPC
Class: |
G06Q
20/341 (20130101); G07F 7/1008 (20130101); G07F
7/125 (20130101); G07F 7/08 (20130101); G07F
7/082 (20130101); G06K 19/073 (20130101) |
Current International
Class: |
G06K
19/073 (20060101); G07F 7/12 (20060101); G07F
7/10 (20060101); G06K 007/10 (); G06K 019/00 () |
Field of
Search: |
;235/375,379,380,382.5,382,459,487 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Smart Cards" by Jose Luis Zoreda et al., pp. 2-7, 1994..
|
Primary Examiner: Porta; David P.
Assistant Examiner: Dunn; Drew A.
Attorney, Agent or Firm: Schneck; Thomas McGuire, Jr.; John
P.
Claims
I claim:
1. A method of validation of an electronic cash card
comprising,
bonding an optical memory stripe to the card,
recording optical validation data on a specific location on the
optical memory stripe by forming a plurality of spots in a
surrounding field of a reflective layer in a laser recording
material,
recording reference validation data in the card reading device,
reading optical data on the optical stripe at the location
specified for the validation data by detecting an optical
reflective contrast between the surrounding field and the recorded
spots,
comparing the optical and reference validation data in the reading
device,
accepting or rejecting the electronic cash card depending upon
whether the optical validation data matches the reference
validation data.
2. The method of claim 1 where said electronic cash card and said
reference validation data are at the same geographical location
during the comparing step.
3. The method of claim 1 where said electronic cash card and said
reference validation data are at different geographical locations
which are electronically linked during the comparing step.
4. The method of claim 1 where the validation data on said optical
memory stripe includes the identification of a card-issuing
institution.
5. The method of claim 4 where at least some of said validation
data was pre-recorded prior to the cards being delivered to the
card-issuing institution whose identification is on said cards.
6. The method of claim 1 where said recorded validation data on
said optical memory stripe includes pre-recorded data by laser or
photolithography.
7. The method of claim 1 where the reference validation data in the
card reading system is limited to a group of specified card-issuing
institutions.
8. The method of claim 1 where said validation data includes some
of the following information: the card serial number, date of card
issuance, geographical location of the issuer and types of
purchases not permitted.
Description
TECHNICAL FIELD
The present invention relates to optical security methods and
apparatus for smart cards.
BACKGROUND ART
Electronic commerce is a method of doing business transactions at a
distance and making payments electronically. The Internet,
interactive networks and cable and ATM machines are being utilized
for electronic commerce. The smart card containing a microchip with
semiconductor memory or microprocessor and memory was invented
about 18 years ago. During the past few years there have been
efforts to store monetary value on such cards which have been
called electronic wallets or electronic purses. One of the better
known cash card systems is known as the Mondex card or Mondex
electronic cash smart cards which is owned by a group of banks and
credit card issuers. The Mondex card system and other electronic
cash smart cards were promoted as being tamperproof. This attracted
the interest of Bell Communications Research (Bellcore) and the
Weizmann Institute and the Technion Institute which undertook
research to break the microchip security codes. They were
successful and reported their results in November 1996 that a valid
electronic cash smart card with its security codes can be
duplicated, that is, counterfeited. The problem facing the
financial institutions was how they could proceed with their plans
to build an electronic commerce industry through the Internet and
other networks when a principal tool, the electronic cash smart
card, was subject to counterfeiting.
It is the object of the present invention to devise a method and
apparatus to inhibit the counterfeiting of electronic cash smart
cards.
DISCLOSURE OF THE INVENTION
The above objective has been met by a smart card having a
pre-formatted optical memory stripe bonded to a plastic wallet-size
substrate containing an electronic cash microchip. The data tracks
on the optical memory stripe would be typically separated by 12
microns or 7.5 microns and would use recorded spots from one to
three microns in diameter. The card validation data would comprise
one thousand to one million of recorded spots.
The validation data could be recorded with a lower power laser
apparatus by the bank or card issuer. The validation data could
also be recorded by the card manufacturer onto the card using
either a low power laser or photolithographic techniques. Under
some security arrangement the validation could comprise recordings
of both the card manufacturer and the card issuer.
Whereas counterfeiters have access to custom microchip
manufacturing, there are only three optical memory card
manufacturers in the world. Each of these three optical card
manufacturers uses different and distinguishing optical storage
media. It requires about $20 million and a high degree of technical
knowhow to build such a manufacturing plant. One such optical
memory card manufacturing plant exists in the U.S.A. and two in
Japan using security controls on the manufacturing and distribution
of the optical memory portion of the card and on the laser writing
apparatus such technology can be kept out of the hands of the
counterfeiters.
The validation data must be read optically and utilized to thwart
the counterfeiter. The method and apparatus for reading the data
will involve either CCD arrays, other photodetector arrays or a
single photodetector. The photodetector array could be of the
linear variety or a single photodetector could be used, in both
cases the card would have to be in motion. In the case of a
two-dimensional photodetector array the card would not require
motion but instead the validation data images would be scanned
electronically. The use of two dimensional CCD arrays to read data
from an optical memory is described in U.S. Pat. Nos. 4,745,484 and
4,864,630. The use of a linear photodetector array to read optical
memory is described in U.S. Pat. No. 4,634,850. The use of a single
photodetector to read an optical memory is described in U.S. Pat.
Nos. 4,500,777 and 4,544,835.
The validation data on the electronic cash smart card is read by a
reading device containing photodetectors and electronically
compared against reference data stored locally to determine the
validity of the electronic cash card before funds are dispersed.
These functions could be carried out in a public kiosk as part of
an electronic commerce system. Just as a vending machine would
reject counterfeit coins or currency the public kiosk would reject
a card not containing key elements of the validation data.
Validation data may also be confirmed by the recipient of the money
transfer. The validation data from the payor's kiosk would be
transmitted to the payee's kiosk where the validation data would be
compared against reference data to determine its validity before
the money transfer would be accepted by the payee.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a smart card in accord with the
present invention.
FIG. 2 is an enlarged view of a thin optical recording strip on a
card in accord with FIG. 1.
FIG. 3 is a plan view of optical apparatus for in-situ writing on
the optical recording material of the card of FIG. 1.
FIG. 4 is a flow chart showing steps in the method of the present
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
With reference to FIG. 1, a smart card 11 is illustrated having a
size common to most credit cards. The card's substrate material 13
is a dielectric, usually a plastic such as polyvinyl chloride or
similar material carrying a chip inside, for example, as shown in
U.S. Pat. Nos. 5,365,655 and 5,134,773. Polycarbonate is preferred.
The surface finish of the base should have low specular
reflectivity, preferably less than 10%.
Substrate 13 carries strip 17. The strip is typically 16 or 35
millimeters wide and extends the length of the card. Alternatively,
the strip may have other sizes and orientations. The strip is
relatively thin, typically 60-200 microns, although this is not
critical. Strips of laser recording material may be applied to both
sides of card 11. The strip may be applied to the card by any
convenient method which achieves flatness.
The strip 17 is adhered to the card with an adhesive and is covered
by a transparent laminating sheet 76 seen in FIG. 2 which serves to
keep strip 17 flat, as well as protecting the strip from dust and
scratches. Sheet 76 is a thin, transparent plastic sheet laminating
material or a coating, such as a transparent lacquer. The material
is preferably made of polycarbonate plastic.
The high resolution laser recording material which forms strip 17
may be any of the reflective recording material which have been
developed for use as direct read-after-write (DRAW) optical disks,
so long as the materials can be formed on thin substrates. An
advantage of reflective materials over transmissive materials is
that the read/write equipment is all on one side of the card, the
data storage capacity is doubled and automatic focus is easier. For
example, the high resolution material described in U.S. Pat. No.
4,230,939 issued to de Bont, et al. teaches a thin metallic
recording layer of reflective metals such as Bi, Te, Ind, Sn, Cu,
Al, Pt, Au, Rh, As, Sb, Ge, Se, Ga.
Materials which are preferred are those having high reflectivity
and low melting point, particularly Cd, Sn, Tl, Ind, Bi and
amalgams. Suspensions of reflective metal surfaces in organic
colloids also form low melting temperature laser recording media.
Silver is one such metal. Typical recording media are described in
U.S. Pat. Nos. 4,314,260, 4,298,684, 4,278,758, 4,278,756 and
4,269,917, all assigned to the assignee of the present
invention.
The laser recording material which is selected should be compatible
with the laser which is used for writing on it. Some materials are
more sensitive than others at certain wavelengths. Good sensitivity
to infrared light is preferred because infrared is affected least
by scratches and dirt on the transparent laminating sheet. The
selected recording material should have a favorable signal-to-noise
ratio and form high contrast data bits with the read/write system
with which it is used.
The material should not lose data when subjected to temperatures of
about 180.degree. F. (82.degree. C.) for long periods. The material
should also be capable of recording at speeds of at least several
thousand bits/sec. This generally precludes the use of materials
that require long heating times or that rely on slow chemical
reactions in the presence of heat, which may permit recording of
only a few bits/sec. A large number of highly reflective laser
recording materials have been used for optical data disk
applications.
Data is recorded by forming spots in the surrounding field of the
reflective layer itself, thereby altering the reflectivity in the
data spot. Data is read by detecting the optical reflective
contrast between the surrounding reflective field of unrecorded
areas and the recorded spots. Spot reflectivity of less than half
the reflectivity of the surrounding field produces a contrast ratio
of at least two to one, which is sufficient contrast for reading.
Greater contrast is preferred. Reflectivity of the strip field of
about 50% is preferred with reflectivity of a spot in the
reflective field being less than 10%, thus creating a contrast
ratio of greater than five to one. Alternatively, data may also be
recorded by increasing the reflectivity of the strip. For example,
the recording laser can melt a field of dull microscopic spikes on
the strip to create flat shiny spots. This method is described in
SPIE, Vol. 329, Optical Disk Technology (1982), p. 202. A spot
reflectivity of more than twice the surrounding spiked field
reflectivity produces a contrast ratio of at least two to one,
which is sufficient contrast for reading.
Data strip 17 is intended to provide a data record and has digital
information indicia. Digital machine readable data is written in
individual tracks extending in a longitudinal direction, as
indicated by the spot patterns 19 and these spot patterns are
analogous to sound track on a film, except that the data tracks
contain a much higher density of information and are usually read
in reflection, rather than in transmission, typically by a CCD
array. The information density is greater because each of the spots
in the spot pattern is approximately 5-10 microns in diameter with
a spacing of about 5-10 microns between spots. The spots are
recorded by a laser in the usual way, for example as shown in U.S.
Pat. No. 4,278,756 to Bouldin et al.
With reference to FIG. 2, a card substrate 70 carries an optional
secondary substrate 72 which is a thin flexible material, only a
few mils thick carrying a laser recording material 74. The
secondary substrate 72 is adhered to the primary substrate 70 by
means of an adhesive or sticky substance, similar to dry adhesives
found on tape. The laser recording material may be any of the
materials previously discussed. A protective coating 76 is applied
over the laser recording material.
A laser writing apparatus is illustrated in FIG. 3 which
illustrates the side view of the lengthwise dimension of the medium
of FIG. 1 consisting of a data strip having digital information in
combination with microscopic visually readable information on a
card. The data strip portion 41 of the medium is usually received
in a movable holder 42 which brings the strip into the trajectory
of a laser beam. A laser light source 43, preferably a pulsed
semiconductor laser of infrared wavelength emits a beam 45 which
passes through collimating and focusing optics 47. The beam is
sampled by a beam splitter 49 which transmits a portion of the beam
through a focusing lens 51 to a photodetector 53. The detector 53
confirms laser writing. The beam is then directed to a first servo
controlled mirror 55 which is mounted for rotation along axis 57 in
the direction indicated by arrows B. The purpose of the mirror 55
is to find the lateral edges of the data strip in a coarse mode of
operation and then in a fine mode of operation identify data paths
or character sites which exist predetermined distances from the
edges.
From mirror 55, the beam is directed toward a mirror 61. This
mirror is mounted for rotation at pivot 63. The purpose of mirror
55 is for fine control of motion of the beam along the length of
the data strip. Coarse control of the lengthwise portion of the
data strip relative to the beam is achieved by motion of the
movable holder 42. The position of the holder may be established by
a linear motor and used by a closed loop position servo system of
the type used in magnetic disk drives. Reference position
information may be prerecorded on the card so that position error
signals may be generated and used as feedback in motor control.
Upon reading one data path, the mirror 55 is slightly rotated. The
motor moves holder 42 lengthwise so that the path can be read
again, and so on.
For writing microscopic visually readable information, mirror 55 is
used to identify character sites at predetermined distances from
the edges. Mirror 57 moves the scanning beam lengthwise from
character site to character site. Upon reading one row of character
sites, mirror 55 is slightly rotated. Within a character site,
mirrors 55 and 57 cooperate to move the beam in either a zig-zag
pattern or a raster-like pattern. Laser spots are written at
designated locations within a character site to form a character.
When one character is written mirrors 55 and 57 move the beam to
the next character site.
As light is scattered and reflected from spots in the laser
recording material, the percentage of reflected light from the
incident beam changes relative to surrounding material where no
spots exist. The incident laser beam should deliver sufficient
laser energy to the surface of the recording material to create
spots in the data writing mode, but should not cause disruption of
the surface so as to cause difficulty in the lower beam power data
reading mode. The wavelength of the laser should be compatible with
the recording material to achieve this purpose. In the read mode,
power is approximately 5% to 10% of the recording or writing
power.
Differences in reflectivity between a spot and surrounding material
are detected by a CCD array, either a linear array or area array.
The number of detector elements per track would be approximately
three elements to create a reading redundancy. The surface would be
illuminated with low-cost light-emitting diodes generating power
primarily in the near infrared to match the sensitivity spectrum of
the photodetector array.
Once a card is prepared, with either prerecorded information on the
optical strip or with laser written information, the extended
information must be sufficiently complex to prevent easy
replication. For example, a pattern of one million spots, being the
digital representation of a random number, might be an
authentication "password" or validation data. A group of numbers,
representing a card serial number, date of card issuance,
geographical location of issuer and types of purchases not
permitted could be encoded with the spots. When this password or
verification data is matched with another password associated with
an electronic reader, a verification signal is generated,
indicating an authentic card. The reader may be linked
electronically with a password server or the passwords may be
stored in a memory local to the reader.
The passwords may be prerecorded by the card manufacturer, using a
photolithography process or a laser process, as described above.
Alternatively, the password may be written by a card-issuing agency
or by both the card manufacturer and the card-issuing agency.
Passwords or validation data could be limited in use to a group of
issuers.
The method of validating the card is summarized in FIG. 4.
Referring to the flow chart, in step 21, an optical memory stripe
would be bonded to an electronic card. Then, in step 23, optical
validation data would be recorded on a specific location on the
optical memory stripe. Next, in step 25, reference validation data
would be recorded in the card reading device. Then, in step 27,
optical data on the optical stripe would be read at the location
specified for the validation data. Then, in step 29, the optical
and reference validation in the reading device are compared. A
decision 80 is then made as to whether the optical and the
reference validation data match. If so, the card is accepted 84. If
the data do not match, the card is rejected 82.
* * * * *